In the video and televised entertainment industry, there is an increasing demand for enhancing the viewing experience of a viewer. Accordingly, there has been numerous innovations to improve the image and the sound of viewings. Motion simulation has also been developed to produce movements of a motion platform (e.g., a seat, a chair) in synchrony with sequences of images of a viewing. For instance, U.S. Pat. Nos. 6,585,515 and 7,934,773 are two examples of systems that have been created to impart motion to a seat, to enhance a viewing experience.
Electro-mechanical linear actuators are commonly used in such motion platforms. These linear actuators must often be capable of producing low and medium amplitude outputs, at low or medium frequency, for a high number of strokes. Moreover, these linear actuators must support a portion of the weight of a platform and its occupant(s).
While the linear actuators expand in their axial dimension to raise a motion platform, the loads applied on the linear actuator are not limited to being in the axial direction, and may have other components, such as radial components, for instance, based on how the linear actuator is connected between the ground and the motion platform. Accordingly, linear actuators may be subjected to loads that could, over time and over cycles, lead them to failure. FIG. 1 shows a prior art driven group of a linear actuator, with a sliding tube piston 1 of the type slidingly received in a cylindrical casing, a threaded shaft 2 and a traveling nut 3 interfacing the threaded shaft 2 to the sliding tube piston 1. It is observed that the traveling nut 3 is secured to the sliding tube piston 1 so as to form an integral unit that moves together. A rotation of the threaded shaft 2 is converted into a translational motion of the sliding tube piston 1, in part because of the traveling nut 3. As loads are applied to the end of the sliding tube piston 1, such loads will be transmitted to the traveling nut 3. Non-axial loads may impact the life of the traveling nut 3 due to the leveraging effect of the sliding tube piston 1 on the traveling nut 3, for such non-axial loads.